Automatic fire-alarm.



J. H. BRUHN, JR. AUTOMATIC FIRE ALARM. APPLICATION FILED OCT. 4. 1910.

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2 SHEETS-SHEET l.

Patented M22127, 1911.

J; H. BRUHN, JR. AUTOMATIG FIRE ALARM. APPLICIATION FILED OUT. 4, 1910.

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355; Y I Pateilteii Mar.7,1911.

:rrnn fsT T srATENT OFFICE.

JOHN H. BRUHN, are, or SPIRIT LAKE, Iowa;

AUTOMATIC FIRE-ALARM."

Specification of Letterslatent.

Patented time. 7,1911.

Application filedfictobere, 1910. Serial No. 585,272;

To all' ulrom it may concern: 7

Be it known-that I, Jonn BRUHN, Jr., a citizen'of the United States,residing at Spirit Lake, in the county of Dickinson,

State of Iowa, have invented certain new and useful Improvements, inAutomatic Fire-Alarms; andI do hereby declare the followingto be a full,clear, and exact description of the invention, such as will en- 1o ableothers skilled in the art to which'it ap- With the above and otherobjects in View the invention consists in general, of certain novelarrangements of details and combinations ofparts hereinafter fullydescribed,

' illustrated in the accompanyingdrawings, a'nd specifically set forthin the claims.

In the accompanying drawings, like char actors of refernce indicate likeparts in the several views, and; Figure 1 is a diagrammatic view showinga telephone system ar ranged in accordance with this invention.

Fig. 2 is a view of .the thermostat used in Jnnection with thisinvention. Fig. 3 is a diagrammatic view showing the wiring of a househaving thermostats at diiferent points The thermostat used in connectionwith this invention is properly speaking a two- V point thermostaticswitch and comprises a base 10 whereon' is mounted a J-shaped metallicframe 11. At the end ofthe stem 0f this frame is an insulator block 12upon which is supported one er of-a thermostatic element 13 consistingof a pair of metallic bars having different linear coeflicients 'ofexpansion under the influence of heat, the bars being rivet d orotherwise secured together as is common in such: devices. On the base10is' a binding post 14 adapted for connection of the line wire as willbe hereinafter d cr bed and throughthe 'base and frame extends a.contact memberf15 which is preferably threaded so that it may be ad'tery 28 connected to the ground at 29; The

justed to suit varyingconditions. This con tact member is connected tothe binding post 14 by means of a wire 16,; Onthe frame 10 is carried aninsulat onblock l7 1 through which passes an adjustable contact member18, the frame being provided with an open ing for said member ofsuflicient size so. that the member 18 does not-at any time 'touch theframe 11, theinsulatingblock preferably being provided with a bushingfitting said opening. These parts are so arranged that under normal heatconditions thethermostatic member 13 will have its free end in contactwith the contact, member 15 while under conditions of increaseof heatthis free end will swing over to, the member 18 and complete a contacttherewith.

The telephone system comprises the usual subscribers, stations 19, theseveral stations" 7 being specifically indicated by the letters,A,: B, Cand B respectively. In the systemhere shown there is indicated as'inglewire system, the return being through the ground and at 20 is indicatedthe ground wire of each station. Ateach of the subscribers stations isan auxiliary battery 21 which is connected to the ground wire at onepoleand to the respectivevcontact 18 at the other pole, The linewiresleading from the sev-- eral stations are indicated. M22 and these linewires are connected to the icontacts '15 of the respective thermostats.It willnzbe seen by reference to Fig. 3 that where more than onethermostat is used in connection with a single subscribers station thether mostats are arranged in series on theline wires 22 and thatthelocalor auxiliary battery 21 is connected in multiple to the contacts18' of the several thermostats. Leading from the thermostats are linewires 23, which run'to thecentral station, each wire passing through theannunciator-system as; typically indicated by the magnets 2 1-. Thewires leading fromthe magnets 24 are connected in multiple. to a "wire,25' which is? wound; around amagnetfcore 26 and from 1 this core passesthroirgh a central telephone station provided with the usual servicebat-1'65 magnet ofwhich 26- is the core constitutes.

'the circuit clo'sing'magnet of a relay indi-' cated in. general at. R[Thisrelay or circuit closer isprovided with a ba e 30 whereon the magnetis supported and on. this base is 110' a fulcrum 31' havingan arm 32pivoted -thereto ,-said am being provided with an magnet. At is a abattery 39 and a bell auxiliary battery in the armature 33 arranged forattraction by the magnet core 26 when the magnet is energized. The baseis of insulating material and secured. thereon is acontact member 34which is arranged to be engaged by the arm 32 when the armature is drawntoward the post which carries a tension screw 36. Connecting the screws36 and the arm 32 is a tension spring 37 which normally urges thearmature 33 away from the magnet but which is arranged in such manner asto permit the-movement of the armature to the magnet when the magnet hasbeen energized to a sufiicient degree. Connected to the contact member34 and to the fulcrum member 31 are the ends of a normally open signalcircuit 38 embracing or other signal 40. The arrangement of the variousparts is such that under the normal conditions arising from the flow ofcurrentfrom the battery 28 through the relay magnet the spring 37 willbe tensioned sufficiently to prevent the armature 33 from being drawntoward the relay magnet and in consequence the circuit 38 whichconstitutes the secondary of the relay williremain open. When, how ever,under abnormal conditions to any one of the telephone stations, thethermostat closes the circuit through't-he battery 21 at that stationand opens the telephone circuit the increased current flow due tocutting in the auxiliary battery 21 will increase the power of themagnet 26 to such extent that the armature 33 will be attracted to themagnet and the circuit 39 and signal 40 closed and the alarm given.Since the wires from the local or subscribers telephone leads throughthe annunciator it will beplain at the same time that the alarm is rungthe 'annunciator drops and indi' cates at which telephone the fire hastaken place and the operator at the central station.

can immediately notify the fire department of the exact location of afire.

In the arrangement of wiring shown inv Fig. 3 it will be obvious thatany one of the thermostats may operate to connect an circuit without theothers being aiiected.

There has thus been provided a simple and ellicient device of the kinddescribed and for the purpose specified.

may be made in the form It is obvious that many minor changes andconstruction of this invention without departing from the materialprinciples thereof. It is not through the battery therefore desired toconfine the invention to the exact form herein shown and described butit is wished to include all such as properly come within the scope ofthe appended claims.

What is claimed is 1. The combination with a main line telephone eircuitincluding a line wire, a local telephone instrument, a central stationannunciator and a two point thermostat switch holding the telephone'incircuit under normal heat conditions, said line wire being connected toone point of said switch and the thermostat element of the switch, abattery connected to the remaining point of said switch, a normally opensignal circuit, a magnetic circuit closer in said signal circuit andhaving its magnetic winding connected to said line wire, and means tohold said circiiihcloser open against current impulses from the localtelephone instrument.

2. The combination with a telephone circuit including a service batteryand a relay inoperable under the battery; of a signal circuit controlledby the relay, a subscribers station-normally in the telephone circuit,an auxiliary battery, and thermostatic means .for substituting theauxiliary battery for the subscribers station in the telephone circuit.7

3. The combination with a telephone circuit including a service batteryand a relay inoperable under the influence of the service battery; of asignal circuit controlled by the relay, a subscribers station, anauxiliary battery and a two point thermostaticswitch in said telephonecircuit and having its points connected respectively to the subscribersstation and the auxiliary battery.

4. The combination with a telephone circuit including a service battery,a relay inoperable under the influence of the service battery, asubscribers station, and a series of two point thermostatic switches; ofan auxiliary battery, a si nal circuit controlled by the relay,aand 'multiple connections between the switches and auxiliary battery wherebythe operation 'of any switch will substitute the auxiliary battery forthesub scribers instrument in the telephone circuit,

In testimony whereof, I aifix my signafl ture, in presence of twowitnesses.

Witnesses WILLIAM H. EHLBEoK, ANNA 'BRUHN.

JOHN 'BRU'HN, JR.

